This is ancient history, but if you're still interested I'll let you know how well a medium fits in my F6. It should be here in a few days.
"If you can control yourself and just loathe us quietly from a distance then by all means stay." - Joe
Leica: M-P Typ 240 - M6 - Leicavit M - RapidWinder - Motor M - 21 Super-Elmar - 28 Ultron - 35 Summicron ASPH - 40 Summicron - 75 APO-Summicron ASPH - 75 Summarit-M - 75 Color-Heliar - 90 Elmar-C
Nikon RF: S2 - S3 2000 - 35/2.5 - 50/2 - 50/1.4 Millennium - 105/2.5 - 135/3.4
X-Pro2, X-M1, X100s, NEX-7, dp0 Quattro, N1V1, N1V2, oodles of other stuff